I have used Unlock Fusion. They seem to be pretty quick with questions, I had my 4S GSM unlocked (ATT). Sold it on craigslist to pay for my upgrade to the 5. The buyer used T-Mobile and no complaints from them. I can't say what other sellers are like because I've only used Unlock Fusion.

I've heard a lot of people doing this. I wonder what back-end option opened up to allow the torrent of unlocking services we have now? (Obviously had something to do with at&t allowing locked iPhones to be unlocked in the first place, but there has to be more to the story)

I have used Unlock Fusion. They seem to be pretty quick with questions, I had my 4S GSM unlocked (ATT). Sold it on craigslist to pay for my upgrade to the 5. The buyer used T-Mobile and no complaints from them. I can't say what other sellers are like because I've only used Unlock Fusion.

I checked unlock_fusion on ebay, they provide unlock service for iPhones priced as low as $1.98. Asking for comments here to make sure if it really works!

I got about 6 unlocks from him so far.
3 iPhone 5 and some 4S and iPhone 4 models.
All are fully unlocked now and they were done within hours from paying for the eBay auction.
Great service from unlock fusion.

I got about 6 unlocks from him so far.
3 iPhone 5 and some 4S and iPhone 4 models.
All are fully unlocked now and they were done within hours from paying for the eBay auction.
Great service from unlock fusion.

I found some sellers selling the service for almost 14 bucks, wondering how unlock fusion can offer such low price $1.98!

There's some that sell it for $50-100 each and others for as little as $1-2
In the end you get the exactly same thing. Ones unlock is not any better or different than the others.
One sells thousands of unlocks and thus just charges less and moves way more imei unlocks.
Another does 5-10 unlocks a week and is happy with that amount of profit I guess.

I've heard a lot of people doing this. I wonder what back-end option opened up to allow the torrent of unlocking services we have now? (Obviously had something to do with at&t allowing locked iPhones to be unlocked in the first place, but there has to be more to the story)

This started after AT&T allowed unlocks for not-in-contract iPhones. Probably some employees at AT&T that just enter the IMEI into a DB, which unlocks the phone. So the seller is either an AT&T employee or knows an AT&T employee that does it. This is why all these unlocks are only for AT&T iPhones. Since this is happening for a while now, it looks like AT&T doesn't care about it.

I've got an IP5 that was unlocked by unlock_fusion and I've had no problems whatsoever including the one mentioned in the other thread. So far I have tested a T-Mobile sim in the US and I'm about to go to France and use it unlocked on Orange.